1. Field of the Invention
This invention relates to a fusible link of the cartridge type used in a vehicle or the like, and more particularly to a structure in which a melted portion, formed as a result of the melting of the fuse, is prevented from being short-circuited.
2. Related Art
FIG. 4 shows one conventional fusible link of the cartridge type used in a vehicle. This fusible link 1 comprises a fuse element 3, an insulating housing 5 containing this fuse element 3, and a transparent cover 7 closing an open top of the insulating housing 5. The fuse element 3 includes a pair of terminal portions 9, leg plates 11 extending respectively from the terminal portions 9, and a fusible portion 13 interconnecting upper ends of the leg plates 11. A pair of through holes 17 are formed through a bottom wall 15 of the insulating housing 5, and retaining grooves 19 are formed respectively in those portions of the upper surface of the bottom wall 15 disposed adjacent respectively to the through holes 17.
In the fusible link 1, the fuse element 3 of an inverted U-shape (in which the terminal portions 9 have not yet been bent) is inserted into the insulating housing 5 through the open top thereof, and the terminal portions 9 are passed respectively through the through holes 17, as shown in FIG. 5. The terminal portions 9 of the fuse element 3, projecting outwardly from the insulating housing, are bent to be disposed parallel to the bottom wall 15, and resilient retaining piece portions 12 are projected inwardly respectively from the two leg plates 11, as shown in FIG. 6.
In the condition shown in FIG. 6, the fuse element 3 of the fusible link 1 is pushed into the insulating housing 5, so that the resilient retaining piece portions 12 are engaged respectively in the retaining grooves 19, and also the terminal portions 9 are held against the lower surface of the bottom wall 15, thereby fixing the fuse element 3 to the insulating housing 5 as shown in FIG. 4.
Incidentally, in a car, even when an engine is in a stopped condition, electric power is supplied to a clock and so on from a battery, and electric current is flowing through the fusible link 1 although its amount is very small. Under the circumstances, if opposed edges of a melted portion are moved toward each other to be again contacted with each other by vibrations or others when exchanging the melted fusible link 1, there has arisen a problem that the melted portion is subjected to so-called secondary short-circuiting. In the above fusible link 1, the fuse element 3 is fixed to the insulating housing 5 by the resilient retaining piece portions 12 and the terminal portions 9, and therefore the opposed edges of the melted portion are opposed to each other only with a gap formed therebetween when the fuse element is melted, and therefore there is a possibility that the above short-circuiting problem is encountered in the above fusible link 1. Furthermore, although the above fusible link 1 is provided with the transparent cover 7, the melting of the fuse element may not be confirmed with the eyes if a gap, formed as a result of the melting, is small, which leads to a possibility that the melted fuse is inadvertently installed.
The present invention has been made in view of the above problems, and an object of the invention is to provide a fusible link in which the short-circuiting is prevented when exchanging a fuse, and the melting of the fuse can be positively noticed.
The above object of the invention has been achieved by a fusible link comprising a fuse element having a pair of terminal portions interconnected by a fusible portion; pivot pawls provided between the fusible portion and each of the terminal portions; seat surfaces respectively supporting the pivot pawls thereon, thereby holding the fuse element within an insulating housing; and pivotal movement-allowing spaces for allowing two portions of the fuse element, separated from each other when the fusible portion is melted, to be pivotally moved about the pivot pawls inside and outside the insulating housing.
In the fusible link of this construction, when the fusible portion is melted, the fuse element is divided or separated into two portions by a melted portion, and the two portions of the fuse element, separated from each other, are held within the insulating housing, with the pivot pawls resting respectively on the seat surfaces, and therefore when the fusible link is lifted, these two portions of the fuse element are pivotally moved about the pivot pawls because of the weights of the terminal portions, so that the opposed edges of the melted portion are moved away from each other. In the melted fusible link, the terminal portions are inclined, and can be pivotally moved about the pivot pawls.